Self-cleaning chlorine generator with pH control

ABSTRACT

A water treatment system includes a circulation pump and an electrolytic chamber in fluid communication with a main body of water. Electrolytic plates within the electrolytic chamber generate chlorine. When mineral deposits foul the electrolytic plates, water is isolated within the electrolytic chamber and a minimal amount of a pH-reducing agent is added to the electrolytic chamber to remove the mineral deposits. In a first embodiment, the pH-reducing agent is admitted on a periodic timed basis. In a second embodiment, the pH-reducing agent is added when the pH of the main body of water falls below a predetermined threshold. In both embodiments, cleaning is accomplished by adding the pH-reducing agent when the circulation pump is not operating so that the acid dwells within the electrolytic chamber for a sufficient amount of time. Activation of the circulation pump causes the pH-reducing agent to enter the main body of water.

CROSS-REFERENCE TO RELATED DISCLOSURE

This disclosure is a divisional application claiming the benefit of thefiling date of U.S. patent application entitled: “Self-Cleaning ChlorineGenerator with pH Control,” filed by the same inventor on Sep. 17, 2004,bearing Ser. No. 10/711,419, now U.S. Pat. No. 7,507,323.

FIELD OF THE INVENTION

This invention relates to electrolytic chlorine generators. Moreparticularly, it relates to means for introducing a pH-reducing agentinto an electrolytic chamber for dissolving mineral deposits fromelectrolytic cells.

DESCRIPTION OF THE PRIOR ART

Electrolytic chlorine generators include electrolytic cells havingplates that are coated on one side or both sides, depending upon thetype of cell, with a platinum group metal (PGM) such as ruthenium, orsimilar coating.

The operation of an electrolytic chlorine generator has the side effectof gradually increasing the pH level of a body of water undergoing suchchlorination. If the pH is too high, it can adversely affect the waterquality and the effectiveness of the chlorine generated by thegenerator. Accordingly, the pH level of a swimming pool, spa, fountain,well, or other body of water equipped with an electrolytic chlorinegenerator and a circulating pump must be lowered periodically.

A pool, spa, fountain, well owner, or the like is required toperiodically perform a test of the water to determine its pH level, andto add muriatic acid or other suitable pH-reducing agent to reduce thelevel if it is too high. The acid has a pH of about 0.1 and thus isextremely dangerous to handle and causes severe burns if it contacts theskin, open wounds, or the eyes.

There is therefore a need for an improved method for adjusting the pH ofwater in circulating water systems equipped with an electrolyticchlorine generator.

Moreover, the electrolytic cells that generate the chlorine are subjectto degradation due to the formation of mineral deposits, typicallycalcium, thereon. The mineral deposits must therefore be removed asneeded.

One prior art technique for cleaning the cells requires manuallyremoving them from the chlorination system and soaking them in acid. Ina typical swimming pool system, such manual cleaning is required aboutevery two weeks. Such manual cleaning is burdensome, risky, and has thedisadvantage of using excessive amounts of acid. The electrolytic cellor block of plates is removed from the circulation line and soaked forapproximately five (5) minutes in a bucket containing a dilutedhydrochloric acid solution of about one (1) part acid to five (5) partswater.

The frequency of manual cleaning may be reduced to quarterly if thepolarity of the electric charge transmitted to the electrolytic platesis periodically reversed. Chlorine is produced on the anode plate or theanode side of a bipolar cell. Thus, in an ideal electrolytic cell, a PGMis applied only to the anode plate or the anode side of a bipolar cell.The cathode plate, or the cathode side of a bipolar cell, is not coatedbecause such plate or side is merely needed to complete the electricalcircuit.

However, in a practical electrolytic cell, the cathode plate and thecathode side of plates in a bipolar cell must also be coated because thepolarity of the anode and cathode must be reversed periodically to cleanthe plates. More particularly, a system that requires polarity reversalis typically operated half the time in one polarity and half the time inthe opposite polarity. A system that does not rely on reverse-polarityoperation would thus reduce the amount of PGM-coated plates by half.

Unfortunately, reversing polarity has detrimental effects on theelectrolytic plates. A PGM coating holds up well during anode operation,but steadily deteriorates during cathode operation. Thus it is desirableto operate PGM-coated plates only on the anode side and the uncoatedplates only on the cathode side. Reversal of polarity results in cathodeoperation of the PGM coated side. Accordingly, cleaning of deposits fromthe plates by reversing the polarity of the anode and cathode should beminimized if not completely avoided. However, most electrolytic chlorinegenerators rely on polarity reversal as the primary means of removingcalcium deposits from the plates.

Moreover, polarity reversal causes the plates to repeatedly charge up,and such charging up wears out the PGM coating at a much faster ratethan steady state operation.

More specifically, charging the plates causes the plates to absorb aminor shock that wears out the PGM coating. This shock can be minimizedby a gradual discharging of the plates, followed by a gradualre-charging at an opposite polarity. This method of reversing polarityis called the “soft start” method and reduces but does not eliminate thewear on the plates. Thus it is beneficial to eliminate or to at leastreduce the number of times that the system is subjected to a reversepolarity, and to use the soft start method when a polarity reversal isrequired.

However, even with routine reversal of polarity, the electrolytic cellswill still collect calcium deposits over time. At least some of thecalcium deposits will eventually flake off and foul the body of water.In a swimming pool or spa, this unsightly debris is eventually suctionedby a pool cleaner or pool drain into a pool filter where the calcium iscollected.

A need therefore exists for a method that will clean calcium depositsfrom electrolytic plates before the calcium flakes off from the plates.

Hardened calcium deposits do not easily dissolve back onto the body ofwater so they remain on the filter until it is removed from the systemand cleaned. The calcium content of the water thus drops over time andrequires replenishment because a swimming pool having low-calcium waterwill aggressively attack various pool walls and equipment.

Thus there is a need for an electrolytic chlorine generator that cleanscalcium deposits from electrolytic plates but which does not result inremoval of calcium from the body of water, and which therefore does notrequire that calcium be added periodically to a body of water.

Electrolytic chlorinators operate best when the salt content of the mainbody of water is between 2800 to 5000 parts per million. This highsalinity adversely affects some swimmers if the main body of water is aswimming pool. Such high salinity may disqualify an electrolyticchlorinator from use where the main body of water is a fountain becausesalt may leave white marks on fixtures after a fixture has been splashedand the splashed water has evaporated.

A need therefore exists for an electrolytic chlorinator that operateswell in a low salt environment.

It is known that the salt content of the water may be reduced if thesurface area of the PGM-coated plates in the electrolytic cell isexponentially increased and the plates are spaced closer together tocompensate for the lower conductivity of the water. Unfortunately,plates that are spaced close to one another become fouled with mineraldeposits at a substantially faster rate than more widely spaced plates.This effect may be countered to some extent by increasing the flow rateof water past the plates and by reversing the polarity of the plates ona more frequent basis. Since maintaining higher flow rates oftenrequires increased energy and equipment expenditures and the increaseduse of polarity reversal wastes the PGM, most systems forego the closerplate spacing and continue to require high salinity.

Thus there is a need for an electrolytic chlorinator that operates wellat lower salt levels without requiring a higher flow rate and withoutincreasing the consumption of PGM.

A general need exists for an improved method for cleaning calcium andother mineral deposits from the electrolytic cells of an electrolyticchlorine generator. The improved method would not have a detrimentaleffect on the electrolytic plates and would eliminate the need forbiweekly or quarterly manual cleaning of the cells.

The improved method would also eliminate or at least substantiallyreduce the need for cleaning the plates by subjecting them to polarityreversal. Such an improved method would thus lower the requisite numberof PGM-coated plates.

Peristaltic pumps for infusing an acidic agent into the line as thecirculation pump is operating are in common use in large commercialfountain and swimming pool installations. However, such pumps areexpensive and are subject to wearing out. There are also systems forinfusing chemicals into the lines that harness the suction created bythe circulation pump to pull the chemicals into the pump. This methodhas the drawback of causing aggressive chemicals such as hydrochloricacid to attack the circulating pump, filters, heaters, and any otherequipment that might be present in the system. Since the pump is thefirst piece on the slab, it is affected the most by such aggressiveagents.

Thus there is a need for an infusing means that infuses aggressivechemicals downstream of the pump and other pieces of equipment that arenot designed to resist aggressive chemicals.

There is also a need for an infusion system that eliminates the need fora pump that is dedicated to infusion.

However, in view of the prior art taken as a whole at the time thepresent invention was made, it was not obvious to those of ordinaryskill how the identified needs could be fulfilled.

SUMMARY OF THE INVENTION

The long-standing but heretofore unfulfilled need for an improved meansfor adjusting the pH of water having chlorine added thereto by anelectrolytic chlorine generator and for cleaning calcium or othermineral deposits from the electrolytic cells of such generator is nowmet by a new, useful, and non-obvious invention.

The inventive structure is a novel chlorine generator that uses thenatural propensity of electrolytic chlorination to increase pH levelsover time as a means to enable the cleansing of an electrolytic chamberby introducing a predetermined volume of a pH-reducing agent into theelectrolytic chamber so that mineral deposits are dissolved from cellplates during a time period that a circulation system is not operating,e.g., during an overnight time period. Advantageously, the novel systemcontrols pH levels in the body of water as well. After the circulationpump is turned off so that water is not circulating through the system,a minimal amount of water is automatically isolated within anelectrolytic cell and a predetermined minimal volume of hydrochloricacid or other suitable pH-reducing agent is automatically introducedinto the electrolytic cell using a gravity feed mechanism or pump. ThepH level in the isolated cell is significantly reduced because thefinite body of water affected by the pH-reducing agent is relativelysmall. The low pH solution dwells within the electrolytic cell overnightor for the duration of the cycle downtime if the system is notcirculating at some other time of day. The lowered pH solution has asmall but consistent and persistent effect on calcium build-up on theplates of the electrolytic cell, gradually dissolving the calcium andhaving a limited, controlled effect on the pH and alkalinity levels inthe main body of water.

A very small amount of pH-reducing agent is required to automaticallyclean the cell because the volume of water in the cell is minimized.Less water enables the use of less pH-reducing chemical. Accordingly,the quantity of pH-reducing agent is minimized by isolating the smallestpossible amount of water within and around the electrolytic cell. Thevolume of water isolated within and around the cell determines theamount of acid necessary to effectively reduce the pH levels and therebyclean the cell.

The novel chlorine generator of this disclosure introduces apredetermined volume of hydrochloric acid, commercially known asmuriatic acid, or an alternative pH-reducing agent into an electrolyticchamber to dissolve mineral deposits from cells overnight.

In a first embodiment, a predetermined volume of a pH-reducing agentsuch as muriatic acid is introduced into the electrolytic chamber on apredetermined, periodic schedule.

In a second embodiment, the pH-reducing agent is added in response tomonitored levels of pH in the main body of water.

In both embodiments, the pH-reducing agent is introduced into theelectrolytic chamber when the circulating pump is not operating. ThepH-reducing agent resident in the electrolytic chamber, after havingbeen used to clean mineral deposits from the electrolytic cells over anextended period of time, is flushed into the main body of water, therebyreducing the pH level in the main body of water, when the watercirculation pump is re-activated.

Significantly, the volume of water within the electrolytic chamber issmall. Thus, only a small amount of pH-reducing agent is required tosubstantially lower the pH of the water in the electrolytic chamber andto thereby cause removal of calcium deposits. Thus, when the circulationpump is re-started, only a small amount of pH-reduced water isintroduced into the swimming pool or other body of water undertreatment. This prevents abrupt drops in the pH level of the body ofwater as a whole. Advantageously, the small injections of reduced pHwater into the body of water serve to maintain the pH within thedesirable range.

Accordingly, the electrolytic cells or plates are not removed from theelectrolytic chamber prior to their cleaning by the muriatic acid. Thisadvantageously saves the time expended in manually removing theelectrolytic plates, cleaning them, and re-installing them. It alsoavoids wasteful use of the pH-reducing agent.

The first embodiment of the self-cleaning chlorine generator includes anelectrolytic chamber having an inlet and an outlet. A circulation pumpis adapted to pump water from a main body of water such as a swimmingpool, spa, fountain, well, or the like through the electrolytic chamber.An electrolytic cell disposed within the electrolytic chamber has aplurality of electrolytic plates. A reservoir of acid is disposed inselective, valved fluid communication with the electrolytic chamber.Specifically, a normally closed valve prevents the acid from flowinginto the electrolytic chamber. A valve actuator connected to thenormally closed valve is adapted to open and close the normally closedvalve.

In the first embodiment, a control means is electrically connected tothe valve actuator and a timer means is electrically connected to thecontrol means. The timer means is adapted to send an “open” signal tothe control means at predetermined times. The “open” signal causes thecontrol means to actuate the valve actuator so that the normally closedvalve is opened for a predetermined amount of time. The timer means isalso adapted to send a “close” signal to the control means atpredetermined times. The “close” signal causes the control means tode-actuate the valve actuator so that the normally closed valve isclosed upon expiration of the predetermined amount of time. Thecirculation pump is in an inactivated state when the timer means sendsthe “open” and “closed” signals to the control means so that acidadmitted into the electrolytic chamber dwells within the electrolyticchamber until the circulation pump is activated. Acid in theelectrolytic chamber cleans mineral deposits from the anode and cathodewhen the circulation pump is not operating. The acid in the electrolyticchamber is introduced into the swimming pool when the circulation pumpis reactivated.

In the second embodiment, a pH sensor disposed in the main body of wateris adapted to generate and send an “open” signal to the control meanswhen the sensor detects that the pH of the water is below apredetermined threshold. The “open” signal causes the control means toactuate the valve actuator so that the normally closed valve is openedfor a predetermined amount of time. The pH sensor means is also adaptedto generate and send a “close” signal to the control means uponexpiration of the predetermined amount of time. The “close” signalcauses the control means to de-actuate the valve actuator so that thenormally closed valve is closed upon expiration of the predeterminedamount of time. The circulation pump is in a deactivated state when thepH sensor means sends the “open” and “closed” signals to the controlmeans so that acid admitted into the electrolytic chamber dwells withinthe electrolytic chamber until the circulation pump is activated. Theacid in the electrolytic chamber cleans mineral deposits from the anodeand cathode when the circulation pump is not operating. The acid in theelectrolytic chamber is introduced into the main body of water when thecirculation pump is activated.

In the first two embodiments, the electrolytic chamber is verticallyoriented and a check valve positioned below the electrolytic chamber isemployed to prevent water from flowing from the chamber to the main bodyof water when the circulation pump is off. In a third embodiment, theelectrolytic chamber is horizontally disposed and is positioned at alower elevation than its inlet and outlet so that water therewithin,when the circulation pump is not running, is trapped and covers theelectrolytic plates in the chamber. This eliminates the need for a checkvalve.

In all embodiments, the pH-reducing agent is preferably muriatic acidand the actuator means is preferably a solenoid valve. Any othersuitable pH-reducing agent and any other actuator means is within thescope of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and objects of the invention,reference should be made to the following detailed description, taken inconnection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of a first embodiment of the invention;

FIG. 1A is a perspective, partially broken away view of the novel capfor closing the pH-reducing agent container;

FIG. 2 is a diagrammatic view of a second embodiment; and

FIG. 3 is a diagrammatic view of a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, it will there be seen that an illustrativeembodiment of the invention is denoted as a whole by the referencenumeral 10.

Novel chlorine generator and plate-cleaning assembly 10 is positioned inline between a circulation pump 12 and return line 14.

Circulation pump 12 draws water from a swimming pool, spa, fountain,well, or other main body of water, not shown, and pumps said waterthrough flow switch 16, one-way check valve 18, electrolytic chamber 20,T-shaped conduit 22, and outlet 14. Electrolytic chamber 20 isvertically oriented.

Cap 24 screw-threadedly engages uppermost branch 22 a of T-shapedconduit 22 and is adapted to screw-threadedly receive ball valve 26.Infusion means 28 surmounts said ball valve 26. Container or reservoir32 surmounts said infusion means 28. Removable cap 34 provides a closuremeans for container 32.

Positioning reservoir 32 above electrolytic chamber 20 as depictedenables a pH-reducing agent in said reservoir to be gravity-fed intosaid chamber. However, this invention is not restricted to gravity-fedsystems. Accordingly, reservoir 32 may be positioned at any elevationbelow said chamber 20 and a pump may be activated when addition ofpH-reducing agent from said reservoir into said chamber is desired.

Water traveling from pump 12 to outlet 14 is therefore constrained topass through electrolytic chamber 20. A plurality of electrolytic anodeand cathode plates, not shown, is mounted within said chamber. Mineraldeposits such as calcium may form on the electrodes as the chlorinegenerator operates in its regular, operatively-polarized mode.

Infusion means 28 includes a timer and a solenoid-controlled valveactuator that controls opening and closing of a normally closed valve.The timer controls the time of opening and closing of the valve and thusthe time that the pH-reducing agent flows into chamber 20 from container32.

One-way check valve 18 has no metal parts so that it is resistant toacidic solutions. It has unions or quick-release couplings 18 a, 18 b tofacilitate its maintenance. One-way check valve 18 may begravity-operated if it is mounted above the level of the body of waterto which it is connected. Water flow thus keeps one-way check valve 18open and gravity closes said valve 18 when such water flow stops. Whenclosed, valve 18 prevents pH-reducing agent in electrolytic chamber 20from flowing into circulation pump 12 and into the main body of water.

Valve 18 may be mounted below the level of the main body of water if itis a tension-type check valve and if “T”-shaped conduit 22 is positionedabove the level of the body of water.

Electrolytic chamber 20 also has unions 20 a, 20 b at its opposite endsfor enhancing maintenance.

Note in FIG. 1 that the reference numeral 21 denotes the water levelwhen pump 12 is not operating. Any water above said water level 21 whencirculation pump 12 is deactivated is drained off through outlet 14.Check valve 18 prevents water from draining towards pump 12 fromelectrolytic chamber 20 when said pump is not running. Thus, thesmallest possible amount of water is isolated within electrolyticchamber 20.

“T”-shaped conduit 22 has three (3) legs 22 a, 22 b, and 22 c. Leg 22 aprovides fluid communication with container 32 and thus enables infusionof the pH-reducing agent in said container into electrolytic chamber 20.Leg 22 b provides fluid communication with electrolytic chamber 20 anddefines high water mark 21. Leg 22 c provides fluid communication withoutlet conduit 14.

Vacuum breaker 15 is needed in some installations to enable water todrain back into the main body of water and to isolate the electrolyticcell.

In a preferred embodiment, the volume of electrolytic chamber 20 isminimized as much as possible without adversely affecting the flow rateand backpressure of the circulation system. Minimizing the volume ofchamber 20 is advantageous because the reduction of the volume of waterin the chamber minimizes the amount of pH-reducing agent required toreduce the pH of that water. It also minimizes the effect that the lowpH water in the electrolytic chamber will have on the main body of waterwhen circulation pump 12 is reactivated.

Ball valve 26 enables a user to control the flow rate of the pH-reducingagent into electrolytic chamber 20 but other less precise controls couldbe used instead of said ball valve. For example, in a proposedcommercial embodiment of the invention, a pre-calibrated narrow openingcould be employed. A small diameter solenoid valve could also be used tolimit the flow rate. Moreover, a flexible and resilient hose could beused to control the flow of pH-reducing agent into chamber 20. Apinching device would pinch the hose to stop flow and would release thehose to start flow. A solenoid is preferred, however, because such ahose is likely to wear out faster than a solenoid.

Controlling the flow rate of pH-reducing agent into electrolytic chamber20 is important because the pH-reducing agent must be added slowlyenough to enable it to sink into and mix properly with the water in saidchamber. If the pH-reducing agent is added too quickly, it can flowdirectly into the main body of water through return line 14 withoutperforming its calcium-removing function.

In this first embodiment, infusion means 28 includes a timer and anormally-closed solenoid-actuated valve. The timer can open the valveonly when circulation pump 12 is not running. The amount of time thatthe valve is open varies depending upon the strength of the pH-reducingagent used and the volume of water within chamber 20. The timer iscalibrated to infuse at least the minimal amount of pH-reducing agentrequired to clean the chamber.

Flow switch 16 includes a flow-sensing means that generates anelectrical signal that disables the timer and solenoid-actuated valve ininfusion means 28 when circulation pump 12 is operating. Theflow-sensing means generates an electrical signal that activates thetimer and solenoid-actuated valve in infusion means 28 when circulationpump 12 is not operating.

The solenoid and valve mounted within infusion means housing 28 arepreferably formed of a resistant polymer or other material that resiststhe corrosive effect of acidic agents and electrolysis.

In a variation of the first embodiment, depicted in FIG. 2, asolenoid-actuated valve is denoted 28 a and a multi-function timer isdenoted 28 b. Thus, this variation differs from the first embodimentonly to the extent that the timer and solenoid arrangement of the firstembodiment are physically separated from one another so thatmulti-function timer 28 b may be used to control the operation of otherfeatures of the circulation system such as the primary circulation pump,waterfalls, a second circulation pump dedicated to a spa, and the like.

Container 32 is preferably secured to a wall or other stable object by astrap joint or other suitable connection means.

Although the first embodiment, the variation thereof, and the secondembodiment depict a gravity-fed system, another embodiment, notdepicted, mounts container 32 below or level with electrolytic chamber20. Such mounting requires the use of a peristaltic pump or equivalentpumping system. Although the addition of an extra pump adds expense tothe system, there is a safety benefit to ground-level mounting ofcontainer 32 due to its hazardous contents.

As best understood in connection with FIG. 1A, cap 34 is preferablyprovided in the form of a two (2) layer cap. Pinhole 35 a is formed intop or outer layer 35 and an offset pinhole 36 a is formed in lower orinner layer 36. Pinholes 35 a and 36 a cooperate to prevent formation ofa vacuum as pH-reducing agent flows out of container 32 into infusionmeans 28. Outer layer 35 helps suppress splashing of pH-reducing agentfrom container 32 if said container is dropped or bumped.

In a third illustrated embodiment, depicted in FIG. 3, electrolyticchamber 20 is oriented in a horizontal disposition to eliminate thecheck valve of the first two depicted embodiments. Water is isolated inelectrolytic cell 20 by means of a horizontally-disposed “U”-shapedtrap. This eliminates the need for a check valve such as check valve 18in the first and second embodiments. As in the other embodiments, thevolume of water within the isolated cell chamber must be minimized sothat cleaning may be accomplished with a minimum of pH reduction.

The “U”-shaped trap is formed by a pair of “S”-shaped conduits 19 a, 19b that are joined by unions 20 a, 20 b, respectively, to inlet 23 a andoutlet 23 b. Said conduits offset chamber 20 downwardly relative to saidinlet and outlet so that water remains in said chamber 20 whencirculation pump 12 is deactivated and water has drained from said inletand outlet as depicted. Note that the water level after such draining isdenoted 21 a. The electrolytic plates in chamber 20 are denoted 21.Water level 21 a is positioned slightly above the respective tops ofsaid plates 21 to ensure immersion of said plates.

Drop-regulating chamber 26 a is positioned downwardly ofsolenoid-activated valve 28 a. An undepicted horizontal wall in chamber26 a has an undepicted pinhole formed therein of predetermined diameterthrough which the pH-reducing agent in container 32 passes, one drop ata time, to enter into electrolytic chamber 20. When circulation pump 12shuts off, the water in the pipes drains to the pool or other main bodyof water, and air from vacuum breaker 15 passes by drop-regulatingchamber 26 a. Air therefore displaces the water within drop-regulatingchamber 26 a, thereby enabling drops of pH-reducing agent to be gravityfed into electrolytic cell 20.

The invention may also be understood to include the method stepsperformed by the apparatus disclosed herein. However, it should beunderstood that different apparatus may be used to perform the methodsteps, i.e., the invention is not limited to the specific apparatus andstructure disclosed herein but is more broadly defined as a method ofcleaning a chlorine generator.

More particularly, the steps of the novel method include providing anelectrolytic chamber having an inlet and an outlet, pumping water from amain body of water through the electrolytic chamber, positioningelectrodes within said electrolytic chamber, positioning a reservoircontaining a pH-reducing agent in selective fluid communication withsaid electrolytic chamber, positioning an infusion means between thereservoir and the electrolytic chamber, controlling flow of thepH-reducing agent from the reservoir through the infusion means and intothe electrolytic chamber so that the pH-reducing agent flows into saidelectrolytic chamber to clean mineral deposits from the electrolyticcell when said circulation pump is not operating, and preventing flow ofthe pH-reducing agent into the electrolytic chamber when the circulationpump is operating.

This method enables the system to operate properly without excessivereduction in pH in the main body of water. The critical aspects of thenovel method include the provision of isolated water in a small chamberand a long dwell time so that a small amount of pH-reducing agent insaid small chamber can dissolve deposits accumulated on the electrolyticplates.

The steps further include positioning a normally closed one-way valveand a valve actuator between a container holding a pH-reducing agent andan electrolytic chamber, adapting the valve actuator to open and closesaid normally closed one-way valve, generating and sending an “open”signal to the actuator means when the normally closed one-way valve isto be opened to release a pH-reducing agent from the container into theelectrolytic chamber; and generating and sending a “close” signal to theactuator means when the normally closed one-way valve is to be closed.

The novel method further includes the steps of positioning a flow switchhaving a flow-sensing means between the circulation pump and theelectrolytic chamber, adapting the flow-sensing means to generate andsend a signal to said actuator means that prevents opening of saidnormally-closed one-way valve when said circulation pump is operating;and adapting the flow-sensing means to generate and send a signal to theactuator means that effects opening of the normally-closed one-way valvewhen the circulation pump is not operating.

Further steps include positioning a check valve, in a system where theelectrolytic chamber is vertically mounted, between the circulation pumpand the inlet of the electrolytic chamber, opening the check valve toallow flow of water from the main body of water into the electrolyticchamber when the circulation pump is operating, and closing the checkvalve to prevent flow of water from the electrolytic chamber to the mainbody of water when the circulation pump is not operating.

In systems where the electrolytic chamber is horizontally mounted, thestep of providing a check valve is eliminated. The electrolytic chamberis positioned at the bottom of a “U”-shaped water trap so that theelectrolytic plates are immersed in water. The inlet and outlet pipes influid communication with the electrolytic chamber are positioned toinsure said immersion. Specifically, the respective bottom surfaces ofsaid inlets and outlets and are positioned at or above the verticalelevation of the top of the electrodes within the chamber. The watertrap electrolytic chamber is installed above the waterline of the mainbody of water to ensure that nearby water lines are drained and a smallamount of water is isolated within the electrolytic chamber forcleansing purposes when the circulation pump turns off. Depending on theparticular site, a vacuum breaker may be required to ensure properdrainage of water from the adjacent pipes.

The novel method requires that the water must be isolated in theelectrolytic cell by means of a check valve (vertical electrolyticchamber), a “U”-shaped trap (horizontal electrolytic chamber), or thelike, and the volume of water within the isolated cell chamber must beminimized so that cleaning may be accomplished with a minimum of pHreduction.

The method steps also include providing a timer adapted to generate andsend an “open” signal to the actuator means at predetermined times andto send a “close” signal to the actuator means at predetermined times sothat the normally closed valve is closed upon expiration of apredetermined amount of time. The circulation pump is deactivated whenthe timer sends the “open” and “closed” signals to the actuator means sothat pH-reducing agent admitted into the electrolytic chamber dwellswithin the electrolytic chamber until the circulation pump is activated.

An alternative method eschews the timer and instead includes the stepsof positioning a pH sensor in the main body of water, adapting the pHsensor to generate and send an “open” signal to the actuator means whenthe sensor detects that the pH of the main body of water is below apredetermined threshold so that the “open” signal causes the actuatormeans to open the normally closed one-way valve, and adapting the pHsensor to generate and send a “close” signal to the actuator means uponexpiration of a predetermined amount of time so that the “close” signalcauses the actuator means to close the normally closed one-way valve.This embodiment also includes deactivating the circulation pump when thesignal generating means sends the “open” and “closed” signals to theactuator means so that pH-reducing agent admitted into the electrolyticchamber dwells within the electrolytic chamber until the circulationpump is activated so that the pH-reducing agent in the electrolyticchamber cleans mineral deposits from the anode and cathode when thecirculation pump is not operating and so that the pH-reducing agent inthe electrolytic chamber is introduced into the body of water when thecirculation pump is activated.

In all embodiments, the method steps are performed overnight or duringextended “off” periods to enable cleaning without over compensation ofpH levels. The acid amount is calibrated depending on the size of thepool and the pH readings. If a cell has been cleaned within the previousten (10) days, the novel system adjusts the pH without letting the acidremain in the cell for an extensive period of time (i.e., the systemturns off the circulation pump, performs the acid infusion, and turnsthe circulation pump back “on” quickly). This process is repeatedperiodically until the proper pH level is achieved. When a chemical feedpump is used to infuse the pH-reducing agent, this pH adjustment may beperformed when the circulation pump is operating.

In all embodiments, the method includes the steps of mounting thereservoir at a preselected elevation above the electrolytic chamber sothat pH-reducing agent in the reservoir flows from the reservoir intothe electrolytic chamber under influence of gravity when the normallyclosed one-way valve is open.

The method further includes the steps of forming the reservoir to havean open top, providing a closure means adapted to close the open top,providing the closure means with an inner lid and an outer lid disposedin vertically spaced apart relation to the inner lid, forming a firstpinhole in the inner lid, and forming a second pinhole in the outer lidso that the first and second pinholes cooperate with one another toadmit ambient air into the reservoir so that the pH-reducing agent mayflow out of the reservoir when the normally closed one-way valve is openand so that the first and second pinholes are misaligned with respect toone another, thereby cooperating with one another to inhibit splashingof the pH-reducing agent from the reservoir when the reservoir isdropped or bumped.

Each pinhole has a one-way flap so that it admits air and keeps thepH-reducing agent in. Thus, the pH-reducing agent does not squirt outfrom the pinholes if the solenoid fails when in its “open” position andwhen the circulation pump is “on,” thereby causing positive pressurebuildup within the reservoir. Other vented splash-proof containers mayalso be used.

In a direct current system, only half of the center plates in theelectrolytic cell need to be coated with a PGM because the coated plateswill continuously remain anode. The other half of the center plates andthe two outside plates will always remain cathode and will thus notrequire any coating. In a preferred embodiment, the coating is aruthenium/iridium combination. Other combinations of PGMs may be usedand a PGM may also be used alone. i.e., not in combination with anyother PGM.

In traditional bipolar chambers, both sides of the plates must becoated. However, the present invention requires that only one side ofeach plate be coated because the electrical charge is delivered fromonly one end of the chamber.

The elimination of the need for reversing polarity also has the benefitof enabling the electrolytic chlorine generator to operate at low saltlevels without increasing the requisite flow rate. Moreover, the novelsystem operates at low salt levels with only half the surface area ofPGM-coated plates of a conventional electrolytic chlorinator operatingat low salt levels. This saves salt and reduces the labor of the personcharged with maintenance of the main body of water. This also reducesthe initial cost of the system by reducing the amount of ruthenium orother PGM-coated plates when a system is purchased. It furthereliminates the need for purchasing equipment to increase the watercirculation speed.

The pH-reducing agent must dwell within the electrolytic chamber for aminimum amount of time, generally no less than four hours, mainlydepending on the concentration of the pH-reducing agent. This allowsample time for the mineral deposits to be dissolved by the acid from theanode and cathode of the electrolytic chamber.

Advantageously, the novel system introduces the pH-reducing agentdownstream of the circulation pump, filter, and other items of equipmentthat are not designed to handle aggressive chemicals. The electrolyticchamber into which the acid is introduced is specifically designed tohandle hydrochloric acid and other pH-reducing agents. Significantly,the electrolytic chamber is the last item of equipment in the linebefore the treated water is returned to the body of water. No equipmentis downstream of the electrolytic chamber. This protects all other itemsof equipment from the effects of the aggressive water containing thepH-reducing agent.

The automatic introduction of a pH-reducing agent into electrolyticchamber 20 has five (5) beneficial effects. First, the pH-reducing agentcleans mineral deposits such as calcium deposits from the electrolyticcells. Such cleaning is required only about once every two weeks.Second, when the circulation pump is re-started, the pH-reducing agentin the electrolytic chamber is pumped into the main body of water,thereby lowering the pH thereof. This is highly desirable due to theinherent pH-increasing effect of electrolytic chlorination. Third, thedissolved calcium is also returned to the main body of water when thecirculation pump is reactivated so that there is no need to add calciumto the main body of water to maintain proper saturation balance. Fourth,the number of expensive, PGM-coated plates is reduced by more than halfby eliminating or substantially reducing the need for cleaning theplates by reversing the polarity of the plates. The PGM-coated platescollectively are the single most expensive part of the entireelectrolytic chlorinator system, so reducing the number of such platesrequired by more than fifty percent (50%) significantly reduces the costof the system. Fifth, the strong self-cleaning characteristic of thepresent invention enables the narrowing of the spaces between theelectrodes, thus enabling substantial lowering of the salinity of themain body of water.

It will thus be seen that the objects set forth above, and those madeapparent from the foregoing description, are efficiently attained andsince certain changes may be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatters contained in the foregoing description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention that, as amatter of language, might be said to fall therebetween.

1. A self-cleaning chlorine generator that forms a part of a circulationsystem for water in a main body of water, comprising: an electrolyticchamber; said electrolytic chamber having an inlet and an outlet; acirculation pump adapted to pump water from a main body of water to saidinlet and through said electrolytic chamber; said outlet of saidelectrolytic chamber being in fluid communication with a return linethat returns water to said main body of water; a control means forisolating the electrolytic chamber from water in said circulation systemand in said main body of water; a plurality of electrolytic platesdisposed within said electrolytic chamber comprising a plurality ofanodes and a plurality of cathodes; a reservoir containing a pH-reducingagent disposed in selective fluid communication with said electrolyticchamber; an infusion means positioned between said reservoir and saidelectrolytic chamber; said control means controlling flow of saidpH-reducing agent from said reservoir through said infusion means andinto said electrolytic chamber; said control means adapted to enablesaid pH-reducing agent to flow into said electrolytic chamber to cleanmineral deposits from said anode and cathode when said circulation pumpis not operating; said control means adapted to prevent flow of saidpH-reducing agent into said electrolytic chamber when said circulationpump is operating; said control means including a normally closedone-way valve and a valve actuator connected to said normally closedone-way valve; said valve actuator adapted to open and close saidnormally closed one-way valve; and said control means including asignal-generating means that generates and sends an “open” signal tosaid actuator means when said normally closed one-way valve is to beopened to release a pH-reducing agent from said reservoir into saidelectrolytic chamber; said control means including saidsignal-generating means that generates and sends a “close” signal to anactuator means when said normally closed one-way valve is to be closed;said control means comprising a pH sensor disposed in said body ofwater, said pH sensor including said signal-generating means adapted togenerate and send said “open” signal to said actuator means when saidsensor detects that the pH of said body of water is below apredetermined threshold, said “open” signal causing said actuator meansto open said normally closed one-way valve; said signal-generating meansalso adapted to generate and send said “close” signal to said actuatormeans upon expiration of a predetermined amount of time, said “close”signal causing said actuator means to close said normally closed one-wayvalve; said circulation pump being in a deactivated state when saidsignal generating means sends said “open” and “closed” signals to saidactuator means so that pH-reducing agent admitted into said electrolyticchamber dwells within said electrolytic chamber until said circulationpump is activated; whereby said pH-reducing agent in said electrolyticchamber cleans mineral deposits from said anode and cathode when saidcirculation pump is not operating; and whereby said pH-reducing agent insaid electrolytic chamber is introduced into said body of water whensaid circulation pump is activated.
 2. The self-cleaningchlorine-generator of claim 1, further comprising: a flow switchpositioned between said circulation pump and said electrolytic chamber;a flow-sensing means positioned within said flow switch; saidflow-sensing means including a signal-generating means that generatesand sends a signal to said actuator means that prevents opening of saidnormally-closed one-way valve when said circulation pump is operating;and said flow-sensing means including a signal-generating means thatgenerates and sends a signal to said actuator means that effects openingof said normally-closed one-way valve when said circulation pump is notoperating.
 3. The self-cleaning chlorine-generator of claim 1, furthercomprising: said electrolytic chamber having a vertical orientationwhere said inlet is below said electrolytic chamber and said outlet isabove said electrolytic chamber; a check valve positioned between saidcirculation pump and said inlet of said electrolytic chamber; said checkvalve being open to allow flow of water from said main body of waterinto said electrolytic chamber when said circulation pump is operating;said check valve being closed to prevent flow of water from saidelectrolytic chamber to said main body of water when said circulationpump is not operating; and a vacuum breaker disposed in said returnline, downstream of said outlet of said electrolytic chamber, to enablewater to drain back into said main body of water to ensure isolation ofsaid electrolytic cell when said circulation pump is not operating. 4.The self-cleaning chlorine-generator of claim 1, further comprising:said electrolytic chamber having a horizontal orientation; said inletand said outlet each having an “S”-shape and being horizontally disposedso that said electrolytic chamber is positioned at an elevation below alowermost surface of said inlet and outlet to ensure that theelectrolytic plates inside said electrolytic chamber are immersed inwater even when all water in adjacent parts of the system has drainedinto the main body of water; vacuum breaker disposed in said inlet,upstream of said outlet of said electrolytic chamber, to enable water todrain back into said main body of water to ensure isolation of saidelectrolytic cell when said circulation pump is not operating.
 5. Theself-cleaning chlorine generator of claim 1, further comprising: saidcontrol means including a timer; said timer adapted to generate and sendan “open” signal to said actuator means at predetermined times; saidtimer adapted to generate and send a “close” signal to said actuatormeans at predetermined times so that said normally closed valve isclosed upon expiration of a predetermined amount of time; saidcirculation pump being in a deactivated state when said timer sends said“open” and “closed” signals to said actuator means so that pH-reducingagent admitted into said electrolytic chamber dwells within saidelectrolytic chamber until said circulation pump is activated.
 6. Theself-cleaning chlorine generator of claim 1, further comprising: saidreservoir being mounted at a preselected elevation above saidelectrolytic chamber so that pH-reducing agent in said reservoir flowsfrom said reservoir into said electrolytic chamber under influence ofgravity when said normally closed one-way valve is open.
 7. Theself-cleaning chlorine generator of claim 1, further comprising: saidreservoir having an open top; a closure means adapted to close said opentop; said closure means having an inner lid and an outer lid disposedinvertically spaced apart relation to said inner lid; a first pinholeformed in said inner lid, said first pinhole having a one-way flap; asecond pinhole formed in said outer lid, said second pinhole having aone-way flap; said first and second pinholes cooperating with oneanother to admit ambient air into said reservoir so that saidpH-reducing agent may flow out of said reservoir when said normallyclosed one-way valve is open; said first and second pinholes beingmisaligned with respect to one another, thereby cooperating with oneanother to inhibit splashing of said pH-reducing agent from saidreservoir when said reservoir is dropped or bumped.
 8. The self-cleaningchlorine generator of claim 1, further comprising: said pH-reducingagent being hydrochloric acid.